Running a small 5,000 BTU 115V Window Air Conditioning Unit

[inetdog]

Just choose between parking the RV is full sun to get maximum power to run the A/C or parking in the shade and not needing as much.
A lot to be said for detachable ground mount panels.

[NEOH]

If the 5,000 BTU A/C unit is run @ 77 F, the unit may work only like 1/4 of its full capacity, so it will cut your calculations to 1/4. @ 77 F there will be no humidity, no sweating, I can sleep very comfortable. Also, there are many things one can do to make the A/C unit to keep the room cool like sealing every hole in the room, install reflective paper on the windows, put some fans in the room to circulate the cool air, etc.

Once the room is cool, the A/C units just has to keep it at that temperature with not much effort.

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

Do you not understand that my calculations showed that your proposed "PV + Battery Bank + A/C" system will work?
So, why the hostility towards real math?
Do you understand the math or not?
You must calculate (know), at a minimum, three parameters for your project ...
1) How many kw-hrs your loads will consume each night
2) How many kw-hrs your pv panels will generate each day
3) How many kw-hrs your batteries can supply before 50% DOD
This requires meaningful calculations!

Without knowing the r-value of the walls, the ceiling and the floor and the temperature differential,
it is extremely difficult to state, as fact, whether the A/C will run at a low 25% Duty Cycle or not.
That is for you to decide, and you can apply that MATH to your project.
No thanks - I will not "blindly trust" any you-tube video.
I prefer to do my own math calculations, that way I know my calculations are appropriate for my project.

[J.P.M.]

Do you not understand that my calculations showed that your proposed "PV + Battery Bank + A/C" system will work?
So, why the hostility towards real math?
Do you understand the math or not?
You must calculate (know), at a minimum, three parameters for your project ...
1) How many kw-hrs your loads will consume each night
2) How many kw-hrs your pv panels will generate each day
3) How many kw-hrs your batteries can supply before 50% DOD
This requires meaningful calculations!

Without knowing the r-value of the walls, the ceiling and the floor and the temperature differential,
it is extremely difficult to state, as fact, whether the A/C will run at a low 25% Duty Cycle or not.
That is for you to decide, and you can apply that MATH to your project.
No thanks - I will not "blindly trust" any you-tube video.
I prefer to do my own math calculations, that way I know my calculations are appropriate for my project.

+1. Start with knowing what you're up against and see what (mental) tools you need. Then fill in the knowledge gaps. All the OP needs here is to keep the horse before the cart, learn what's needed in order to understand what's happening, and then match what's available to meet the as yet undefined load/goal. Doing so may lead to a project that initially involves more learning than doing, and then sealing/insulating, and measuring/estimating/defining a load. While doing that, the OP may perhaps discover that, at least in its current state of development, PV is mostly not as cost effective or practical r as much of a cake walk for small, off grid applications as the solar peddlers and their tree hugging shills would want the solar ignorant to believe. Knowledge is power.

[LETitROLL]

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

That is one of the funniest things i have ever seen my whole life, those "meaningless calculations" are physics, a measurable, precise, unchangeable force of this universe. If you are only looking to "play" and experiment around with temporary, short, lived, patched together systems, that will need components replaced or upgraded often (Expensive), or only to cool a small amount on certain days, then lots of things will work.The answers you have gotten here with the "meaningless calculations" in them are for real world, properly working, long term working without too much trouble systems, that can cool well in varying conditions. Lots of things can be done, what you are looking to do can be easily done, but math makes is certain that you will either spend a lot of Money, or not get much cooling over the long haul, you can get a lot of cooling for a short time, and then buy a new inverter, or more batteries, or you can use "meaningless calculations" to properly design a system that does not nickel and dime you to the poor house. Math dictates how each system will work, not tricks, or luck, so in the end every system will succeed or fail based on the math (even the systems on Youtube). As was mentioned earlier, the only "trick" than can get you more cooling for not too much more money, and still satisfy the math that makes the cold air come out of the vent in the first place, is a mostly daytime system with more panels, and not too much after sundown battery use. Not one person in this universe has ever been able to trick, or defeat math yet, so you can go with it, or learn the hard way (expensive or warm air).

[J.P.M.]

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

U-tube == The new idiot's bible.

[Logan5]

If the 5,000 BTU A/C unit is run @ 77 F, the unit may work only like 1/4 of its full capacity, so it will cut your calculations to 1/4. @ 77 F there will be no humidity, no sweating, I can sleep very comfortable. Also, there are many things one can do to make the A/C unit to keep the room cool like sealing every hole in the room, install reflective paper on the windows, put some fans in the room to circulate the cool air, etc.

Once the room is cool, the A/C units just has to keep it at that temperature with not much effort.

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

But, everybody's doing it. look see..

[J.P.M.]

But, everybody's doing it. look see..

Not everyone, but maybe a lot of those who feel justified suspending the need for critical observation/thinking and so only see what they want to see.

[Sunking]

Also, I'm thinking on building my own air conditioning unit that would spend no more than 70 watts @12V. 500 watts it is way too much.

Complete hogwash. That would mean the EER would have to be 5000 Btus/ 70 watts = 71.

You would be an extremely rich man if you could do that, and the Laws of Physics would have to be rewritten. Best units made today are EER of 26 to 25. You are full of crap millennial.

[J.P.M.]

Complete hogwash. That would mean the EER would have to be 5000 Btus/ 70 watts = 71.

You would be an extremely rich man if you could do that, and the Laws of Physics would have to be rewritten. Best units made today are EER of 26 to 25. You are full of crap millennial.

While I agree that thinking you can build your own A/C unit shows a lot of is naivety as to what the task entails, I'd add that learning how to calculate what the load to be met actually is might be a better first step to meet the goal the OP describes.

[Sunking]

While I agree that thinking you can build your own A/C unit shows a lot of is naivety as to what the task entails, I'd add that learning how to calculate what the load to be met actually is might be a better first step to meet the goal the OP describes.

JPM you and I know this will never happen. He does not even understand 5th grade math.

[bcroe]

How would you go about building your own A/C unit ?

I actually worked with a couple (already ancient) home cooler units in the 50s, which used a belt
to drive the compressor. Guess a DC motor could be substituted, don't know how much varying
rpm would affect the efficiency. Or do it with an automotive unit. Bruce Roe

[SWFLA]

Variable speed rotary DC inverter tough to beat. No surge current. Watt sipper once things are cooled down.

[J.P.M.]

JPM you and I know this will never happen. He does not even understand 5th grade math.

Maybe, but not mentioning it sort of seems like giving tacit approval to the ignorance and an excuse to not make it a necessary 1st step which, as you well know, usually starts by identifying a need and then defining the parameters of the need. As in: "I need a way to remove X amount of heat from this space when it's this hot". I can rag on the OP all I want, but without some constructive criticism or direction, I'm doing squat that's productive. Having said my peace, the OP can then take it or leave it as wanted.

[SWFLA]

Start with a manual J calculation it's all out there.

[J.P.M.]

You know, if I was one of the professional engineers here who has volunteered to help you on his own time, I'd find that last statement to be pretty damned insulting. Calling the information you've received "meaningless calculations" is effectively telling them that the time and money they've invested in their education, years in training, and passing the PE amounted to nothing. This is how you thank them? Now I know why Dereck and Russ are the way they are.

Seems that a side bennie of being a P.E. (and now retired) is having a bit of a tough skin. Can't speak for others, but I'm not insulted in the least by ignorance. If I did, I'd be insulting myself a lot. However, in others, I won't waste a lot of time on the arrogant bullheadedness that allows ignorance to persist.